Archaeologists have found 4,000-year-old characters, even older than the oracle bones scripts, in north China's Inner Mongolia Autonomous Region.

Ink marks, which were confirmed to be three or four characters, were found on a pottery piece unearthed at Gaojiataizi, the ruins of the Lower Xiajiadian Culture in the city of Chifeng, Lian Jilin, with the regional research institute of cultural heritage and archaeology, said Sunday.

The ruins, an area of over 10,000 square meters, were jointly excavated by the institute and Jilin University.

Experts from the National Museum of China confirmed the marks were characters left by animal-fur brush with ink, said Lian.

The words, which were written smoothly, are believed to be connected with sacrificial activities.

Pottery scripts, together with those of oracle bones and bronze objects, have been known for long term preservation.

"The oracle bones, scripts from some 3,000 years ago in the Shang Dynasty, may have originated from the pottery scripts," he said, adding the discovery has offered new evidence to trace the origin of oracle bones.

Pottery and stone articles, as well as animal bones were also unearthed at the ruins.

The Lower Xiajiadian Culture, a branch of the northern bronze culture during the Xia and Shang dynasties, dates back to 3,500-4,000 years ago, between the late Neolithic Age and Bronze Age.

The Lower Xiajiadian site in Chifeng was listed as one of the top archaeological discoveries in China in 2009.